CXCL8 and breast cancer: A molecular signature, PETsign, is derived from breast cancer (BC) patients stratified by ‐ positron emission tomography.  PETsign recapitulates the metabolic activity of BCs and is an independent predictor of disease outcome. C‐X‐C motif chemokine ligand 8 (CXCL8) and epidermal growth factor receptor (EGFR) signaling pathways are prominent in PETsign, and their activation in BC cells causes a shift toward a glycolytic phenotype.